Enlightenment Now: The Case for Reason, Science, Humanism, and Progress

CHAPTER 11 PEACE

How deep do the currents of progress flow? Can they suddenly come to a halt or go into reverse? The history of violence provides an opportunity to confront these questions. In The Better Angels of Our Nature I showed that, as of the first decade of the 21st century, every objective measure of violence had been in decline. As I was writing it, reviewers warned me that it could all explode before the first copy hit the stores. (A war, possibly nuclear, between Iran and either Israel or the United States was the worry of the day.) Since the book was published in 2011, a cascade of bad news would seem to make it obsolete: civil war in Syria, atrocities in the Islamic State, terrorism in Western Europe, autocracy in Eastern Europe, shootings by police in the United States, and hate crimes and other outbursts of racism and misogyny from angry populists throughout the West.

But the same Availability and Negativity biases that made people incredulous about the possibility that violence had declined can make them quick to conclude that any decline has been reversed. In the next five chapters I will put the recent bad news in perspective by going back to the data. I’ll plot the historical trajectories of several kinds of violence up to the present, including a reminder of the last data point available when The Better Angels of Our Nature went to press.¹ Seven years or so is an eyeblink in history, but it offers a crude indication of whether the book capitalized on a lucky instant or identified an ongoing trend. More important, I’ll try to explain the trends in terms of deeper historical forces, placing them within the narrative of progress that is the subject of this book. (In doing so I’ll introduce some new ideas on what those forces are.) I’ll begin with the most extravagant form of violence, war.

For most of human history, war was the natural pastime of governments, peace a mere respite between wars.² This can be seen in figure 11-1, which plots the proportion of time over the last half-millennium that the great powers of the day were at war. (Great powers are the handful of states and empires that can project force beyond their borders, that treat each other as peers, and that collectively control a majority of the world’s military resources.)³ Wars between great powers, which include world wars, are the most intense forms of destruction our sorry species has managed to dream up, and they are responsible for a majority of the victims of all wars combined. The graph shows that at the dawn of the modern era the great powers were pretty much always at war. But nowadays they are never at war: the last one pitted the United States against China in Korea more than sixty years ago.

Figure 11-1: Great power war, 1500–2015

Source: Levy & Thompson 2011, updated for the 21st century. Percentage of years the great powers fought each other in wars, aggregated over 25-year periods, except for 2000–2015. The arrow points to 1975–1999, the last quarter-century plotted in fig. 5–12 of Pinker 2011.

The jagged decline of great power war conceals two trends that until recently went in opposite directions.⁴ For 450 years, wars involving a great power became shorter and less frequent. But as their armies became better manned, trained, and armed, the wars that did take place became more lethal, culminating in the brief but stunningly destructive world wars. It was only after the second of these that all three measures of war—frequency, duration, and lethality—declined in tandem, and the world entered the period that has been called the Long Peace.

It’s not just the great powers that have stopped fighting each other. War in the classic sense of an armed conflict between the uniformed armies of two nation-states appears to be obsolescent.⁵ There have been no more than three in any year since 1945, none in most years since 1989, and none since the American-led invasion of Iraq in 2003, the longest stretch without an interstate war since the end of World War II.⁶ Today, skirmishes between national armies kill dozens of people rather than the hundreds of thousands or millions who died in the all-out wars that nation-states have fought throughout history. The Long Peace has certainly been tested since 2011, such as in conflicts between Armenia and Azerbaijan, Russia and Ukraine, and the two Koreas, but in each case the belligerents backed down rather than escalating into all-out war. This doesn’t, of course, mean that escalation to major war is impossible, just that it is considered extraordinary, something that nations try to avoid at (almost) all costs.

The geography of war also continues to shrink. In 2016 a peace agreement between the government of Colombia and Marxist FARC guerrillas ended the last active political armed conflict in the Western Hemisphere, and the last remnant of the Cold War. This is a momentous change from just decades before.⁷ In Guatemala, El Salvador, and Peru, as in Colombia, leftist guerrillas battled American-backed governments, and in Nicaragua it was the other way around (American-backed contras battling a left-wing government), in conflicts that collectively killed more than 650,000 people.⁸ The transition of an entire hemisphere to peace follows the path of other large regions of the world. Western Europe’s bloody centuries of warfare, culminating in the two world wars, have given way to more than seven decades of peace. In East Asia, the wars of the mid-20th century took millions of lives—in Japan’s conquests, the Chinese Civil War, and the wars in Korea and Vietnam. Yet despite serious political disputes, East and Southeast Asia today are almost entirely free from active interstate combat.

The world’s wars are now concentrated almost exclusively in a zone stretching from Nigeria to Pakistan, an area containing less than a sixth of the world’s population. Those wars are civil wars, which the Uppsala Conflict Data Program (UCDP) defines as an armed conflict between a government and an organized force which verifiably kills at least a thousand soldiers and civilians a year. Here we find some recent cause for discouragement. A precipitous decline in the number of civil wars after the end of the Cold War—from fourteen in 1990 to four in 2007—went back up to eleven in 2014 and 2015 and to twelve in 2016.⁹ The flip is driven mainly by conflicts that have a radical Islamist group on one side (eight of the eleven in 2015, ten of the twelve in 2016); without them, there would have been no increase in the number of wars at all. Perhaps not coincidentally, two of the wars in 2014 and 2015 were fueled by another counter-Enlightenment ideology, Russian nationalism, which drove separatist forces, backed by Vladimir Putin, to battle the government of Ukraine in two of its provinces.

The worst of the ongoing wars is in Syria, where the government of Bashar al-Assad has pulverized his country in an attempt to defeat a diverse set of rebel forces, Islamist and non-Islamist, with the assistance of Russia and Iran. The Syrian civil war, with 250,000 battle deaths as of 2016 (conservatively estimated), is responsible for most of the uptick in the global rate of war deaths shown in figure 11-2.¹⁰

Figure 11-2: Battle deaths, 1946–2016

Sources: Adapted from Human Security Report Project 2007. For 1946–1988: Peace Research Institute of Oslo Battle Deaths Dataset 1946–2008, Lacina & Gleditsch 2005. For 1989–2015: UCDP Battle-Related Deaths Dataset version 5.0, Uppsala Conflict Data Program 2017, Melander, Pettersson, & Themnér 2016, updated with information from Therese Pettersson and Sam Taub of UCDP. World population figures: 1950–2016, US Census Bureau; 1946–1949, McEvedy & Jones 1978, with adjustments. The arrow points to 2008, the last year plotted in fig. 6–2 of Pinker 2011.

That uptick, however, comes at the end of a vertiginous six-decade plunge. World War II at its worst saw almost 300 battle deaths per 100,000 people per year; it is not shown in the graph because it would have scrunched the line for all subsequent years into a wrinkled carpet. In the postwar years, as the graph shows, the rate of deaths roller-coastered downward, cresting at 22 during the Korean War, 9 during the Vietnam War in the late 1960s and early 1970s, and 5 during the Iran-Iraq War in the mid-1980s, before bobbing along the floor at less than 0.5 between 2001 and 2011. It crept up to 1.5 in 2014 and subsided to 1.2 in 2016, the most recent year for which data are available.

Followers of the news in the mid-2010s might have expected the Syrian carnage to have erased all of the historic progress of the preceding decades. That’s because they forget the many civil wars that ended without fanfare after 2009 (in Angola, Chad, India, Iran, Peru, and Sri Lanka) and also forget earlier ones with massive death tolls, such as the wars in Indochina (1946–54, 500,000 deaths), India (1946–48, a million deaths), China (1946–50, a million deaths), Sudan (1956–72, 500,000 deaths, and 1983–2002, a million deaths), Uganda (1971–78, 500,000 deaths), Ethiopia (1974–91, 750,000 deaths), Angola (1975–2002, a million deaths), and Mozambique (1981–92, 500,000 deaths).¹¹

Searing images of desperate refugees from the Syrian civil war, many of them struggling to resettle in Europe, have led to the claim that the world now has more refugees than at any time in history. But this is another symptom of historical amnesia and the Availability bias. The political scientist Joshua Goldstein notes that today’s four million Syrian refugees are outnumbered by the ten million displaced by the Bangladesh War of Independence in 1971, the fourteen million displaced by the partition of India in 1947, and the sixty million displaced by World War II in Europe alone, eras when the world’s population was a fraction of what it is now. Quantifying this misery is by no means callous to the terrible suffering of today’s victims. It honors the suffering of yesterday’s victims, and it ensures that policymakers will act in their interests by working from an accurate understanding of the world. In particular, it should prevent them from drawing dangerous conclusions about “a world at war,” which could tempt them to scrap global governance or return to a mythical “stability” of Cold War confrontation. “The world is not the problem,” Goldstein notes; “Syria is the problem. . . . The policies and practices that ended wars [elsewhere] can with effort and intelligence end wars today in South Sudan, Yemen, and perhaps even Syria.”¹²

Mass killings of unarmed civilians, also known as genocides, democides, or one-sided violence, can be as lethal as wars and often overlap with them. According to the historians Frank Chalk and Kurt Jonassohn, “Genocide has been practiced in all regions of the world and during all periods in history.”¹³ During World War II, tens of millions of civilians were slaughtered by Hitler, Stalin, and imperial Japan, and in deliberate bombings of civilian areas by all sides (twice with nuclear weapons); at its peak the death rate was about 350 per 100,000 per year.¹⁴ But contrary to the assertion that “the world has learned nothing from the Holocaust,” the postwar period has seen nothing like the blood flood of the 1940s. Even within the postwar period, the rate of deaths in genocides has juddered down a steep sawtooth, as we see in two datasets shown in figure 11-3.

Figure 11-3: Genocide deaths, 1956–2016

Sources: PITF, 1955–2008: Political Instability Task Force State Failure Problem Set, 1955–2008, Marshall, Gurr, & Harff 2009; Center for Systemic Peace 2015. Calculations described in Pinker 2011, p. 338. UCDP, 1989–2016: UCDP One-Sided Violence Dataset v. 2.5-2016, Melander, Pettersson, & Themnér 2016; Uppsala Conflict Data Program 2017, “High fatality” estimates, updated with data provided by Sam Taub of UCDP, scaled by world population figures from US Census Bureau. The arrow points to 2008, the last year plotted in fig. 6–8 of Pinker 2011.

The peaks in the graph correspond to mass killings in the Indonesian anti-Communist “year of living dangerously” (1965–66, 700,000 deaths), the Chinese Cultural Revolution (1966–75, 600,000), Tutsis against Hutus in Burundi (1965–73, 140,000), the Bangladesh War of Independence (1971, 1.7 million), north-against-south violence in Sudan (1956–72, 500,000), Idi Amin’s regime in Uganda (1972–79, 150,000), Pol Pot’s regime in Cambodia (1975–79, 2.5 million), killings of political enemies in Vietnam (1965–75, 500,000), and more recent massacres in Bosnia (1992–95, 225,000), Rwanda (1994, 700,000), and Darfur (2003–8, 373,000).¹⁵ The barely perceptible swelling from 2014 to 2016 includes the atrocities that contribute to the impression that we are living in newly violent times: at least 4,500 Yazidis, Christians, and Shiite civilians killed by ISIS; 5,000 killed by Boko Haram in Nigeria, Cameroon, and Chad; and 1,750 killed by Muslim and Christian militias in the Central African Republic.¹⁶ One can never use the word “fortunately” in connection with the killing of innocents, but the numbers in the 21st century are a fraction of those in earlier decades.

Of course, the numbers in a dataset cannot be interpreted as a direct readout of the underlying risk of war. The historical record is especially scanty when it comes to estimating any change in the likelihood of very rare but very destructive wars.¹⁷ To make sense of sparse data in a world whose history plays out only once, we need to supplement the numbers with knowledge about the generators of war, since, as the UNESCO motto notes, “Wars begin in the minds of men.” And indeed we find that the turn away from war consists in more than just a reduction in wars and war deaths; it also may be seen in nations’ preparations for war. The prevalence of conscription, the size of armed forces, and the level of global military spending as a percentage of GDP have all decreased in recent decades.¹⁸ Most important, there have been changes in the minds of men (and women).

How did it happen? The Age of Reason and the Enlightenment brought denunciations of war from Pascal, Swift, Voltaire, Samuel Johnson, and the Quakers, among others. It also saw practical suggestions for how to reduce or even eliminate war, particularly Kant’s famous essay “Perpetual Peace.”¹⁹ The spread of these ideas has been credited with the decline in great power wars in the 18th and 19th centuries and with several hiatuses in war during that interval.²⁰ But it was only after World War II that the pacifying forces identified by Kant and others were systematically put into place.

As we saw in chapter 1, many Enlightenment thinkers advanced the theory of gentle commerce, according to which international trade should make war less appealing. Sure enough, trade as a proportion of GDP shot up in the postwar era, and quantitative analyses have confirmed that trading countries are less likely to go to war, holding all else constant.²¹

Another brainchild of the Enlightenment is the theory that democratic government serves as a brake on glory-drunk leaders who would drag their countries into pointless wars. Starting in the 1970s, and accelerating after the fall of the Berlin Wall in 1989, more countries gave democracy a chance (chapter 14). While the categorical statement that no two democracies have ever gone to war is dubious, the data support a graded version of the Democratic Peace theory, in which pairs of countries that are more democratic are less likely to confront each other in militarized disputes.²²

The Long Peace was also helped along by some realpolitik. The massive destructive powers of the American and Soviet armies (even without their nuclear weapons) made the Cold War superpowers think twice about confronting each other on the battlefield—which, to the world’s surprise and relief, they never did.²³

Yet the biggest single change in the international order is an idea we seldom appreciate today: war is illegal. For most of history, that was not the case. Might made right, war was the continuation of policy by other means, and to the victor went the spoils. If one country felt it had been wronged by another, it could declare war, conquer some territory as compensation, and expect the annexation to be recognized by the rest of the world. The reason that Arizona, California, Colorado, Nevada, New Mexico, and Utah are American states is that in 1846 the United States conquered them from Mexico in a war over unpaid debts. That cannot happen today: the world’s nations have committed themselves to not waging war except in self-defense or with the approval of the United Nations Security Council. States are immortal, borders are grandfathered in, and any country that indulges in a war of conquest can expect opprobrium, not acquiescence, from the rest.

The legal scholars Oona Hathaway and Scott Shapiro argue that it’s the outlawry of war that deserves much of the credit for the Long Peace. The idea that nations should agree to make war illegal was proposed by Kant in 1795. It was first agreed upon in the much-ridiculed 1928 Pact of Paris, also known as the Kellogg-Briand pact, but really became effective only with the founding of the United Nations in 1945. Since then, the conquest taboo has occasionally been enforced with a military response, such as when an international coalition reversed Iraq’s conquest of Kuwait in 1990–91. More often the prohibition has functioned as a norm—“War is something that civilized nations just don’t do”—backed by economic sanctions and symbolic punishments. Those penalties are effective to the extent that nations value their standing in the international community—a reminder of why we should cherish and strengthen that community in the face of threats from populist nationalism today.²⁴

To be sure, the norm is sometimes honored in the breach, most recently in 2014, when Russia annexed Crimea. This would seem to confirm the cynical view that until we have a world government, international norms are toothless and will be flouted with impunity. Hathaway and Shapiro reply that laws within a country are broken, too, from parking violations to homicides, yet an imperfectly enforced law is better than no rule of law at all. The century before the Paris Peace Pact, they calculate, saw the equivalent of eleven Crimea-sized annexations a year, most of which stuck. But virtually every acre of land that was conquered after 1928 has been returned to the state that lost it. Frank Kellogg and Aristide Briand (the US secretary of state and the French foreign minister) may deserve the last laugh.

Hathaway and Shapiro point out that the outlawry of interstate war had a downside. As European empires vacated the colonial territories they had conquered, they often left behind weak states with fuzzy borders and no single recognized successor to govern them. The states often fell into civil war and intercommunal violence. Under the new international order, they were no longer legitimate targets of conquest by more effective powers, and hung on in semi-anarchy for years or decades.

The decline of interstate war was still a magnificent example of progress. Civil wars kill fewer people than interstate wars, and since the late 1980s civil wars have declined as well.²⁵ When the Cold War ended, the great powers became less interested in who won a civil war than in how to end it, and they supported UN peacekeeping forces and other international posses which inserted themselves between belligerents and, more often than not, really did keep the peace.²⁶ Also, as countries get richer, they become less vulnerable to civil war. Their governments can afford to provide services like health care, education, and policing and thus outcompete rebels for the allegiance of their citizens, and they can regain control of the frontier regions that warlords, mafias, and guerrillas (often the same people) stake out.²⁷ And since many wars are ignited by the mutual fear that unless a country attacks preemptively it will be annihilated by a preemptive attack (the game-theoretic scenario called a security dilemma or Hobbesian trap), the alighting of peace in a neighborhood, whatever its first cause, can be self-reinforcing. (Conversely, war can be contagious.)²⁸ That helps explain the shrinking geography of war, with most regions of the globe at peace.

Together with ideas and policies that reduce the incidence of war, there has been a change in values. The pacifying forces we have seen so far are, in a sense, technological: they are means by which the odds can be tilted in favor of peace if it’s peace that people want. At least since the folk-song-and-Woodstock ’60s, the idea that peace is inherently worthy has become second nature to Westerners. When military interventions have been launched they have been rationalized as regrettable but necessary measures to prevent greater violence. But not so long ago it was war that was considered worthy. War was glorious, thrilling, spiritual, manly, noble, heroic, altruistic—a cleansing purgative for the effeminacy, selfishness, consumerism, and hedonism of decadent bourgeois society.²⁹

Today, the idea that it is inherently noble to kill and maim people and destroy their roads, bridges, farms, dwellings, schools, and hospitals strikes us as the raving of a madman. But during the 19th-century counter-Enlightenment, it all made sense. Romantic militarism became increasingly fashionable, not just among Pickelhaube-topped military officers but among many artists and intellectuals. War “enlarges the mind of a people and raises their character,” wrote Alexis de Tocqueville. It is “life itself,” said Émile Zola; “the foundation of all the arts . . . [and] the high virtues and faculties of man,” wrote John Ruskin.³⁰

Romantic militarism sometimes merged with romantic nationalism, which exalted the language, culture, homeland, and racial makeup of an ethnic group—the ethos of blood and soil—and held that a nation could fulfill its destiny only as an ethnically cleansed sovereign state.³¹ It drew strength from the muzzy notion that violent struggle is the life force of nature (“red in tooth and claw”) and the engine of human progress. (This can be distinguished from the Enlightenment idea that the engine of human progress is problem-solving.) The valorization of struggle harmonized with Friedrich Hegel’s theory of a dialectic in which historical forces bring forth a superior nation-state: wars are necessary, Hegel wrote, “for they save the state from social petrifaction and stagnation.”³² Marx adapted the idea to economic systems and prophesied that a progression of violent class conflicts would climax in a communist utopia.³³

But perhaps the biggest impetus to romantic militarism was declinism, the revulsion among intellectuals at the thought that ordinary people seemed to be enjoying their lives in peace and prosperity.³⁴ Cultural pessimism became particularly entrenched in Germany through the influence of Schopenhauer, Nietzsche, Jacob Burckhardt, Georg Simmel, and Oswald Spengler, author in 1918–23 of The Decline of the West. (We will return to these ideas in chapter 23.) To this day, historians of World War I puzzle over why England and Germany, countries with a lot in common—Western, Christian, industrialized, affluent—would choose to hold a pointless bloodbath. The reasons are many and tangled, but insofar as they involve ideology, Germans before World War I “saw themselves as outside European or Western civilization,” as Arthur Herman points out.³⁵ In particular, they thought they were bravely resisting the creep of a liberal, democratic, commercial culture that had been sapping the vitality of the West since the Enlightenment, with the complicity of Britain and the United States. Only from the ashes of a redemptive cataclysm, many thought, could a new heroic order arise. They got their wish for a cataclysm. After a second and even more horrific one, the romance had finally been drained from war, and peace became the stated goal of every Western and international institution. Human life has become more precious, while glory, honor, preeminence, manliness, heroism, and other symptoms of excess testosterone have been downgraded.

Many people refuse to believe that progress toward peace, however fitful, could even be possible. Human nature, they insist, includes an insatiable drive for conquest. (And not just human nature; some commentators project the megalomania of Homo sapiens males onto every form of intelligence, warning that we must not search for extraterrestrial life lest an advanced race of space aliens discovers our existence and comes over to subjugate us.) While a vision of world peace may have given John and Yoko some good songs, it is hopelessly naïve in the real world.

In fact, war may be just another obstacle an enlightened species learns to overcome, like pestilence, hunger, and poverty. Though conquest may be tempting over the short term, it’s ultimately better to figure out how to get what you want without the costs of destructive conflict and the inherent hazards of living by the sword, namely that if you are a menace to others you have given them an incentive to destroy you first. Over the long run, a world in which all parties refrain from war is better for everyone. Inventions such as trade, democracy, economic development, peacekeeping forces, and international law and norms are tools that help build that world.